No doubt, Hammurabi's Babylon closely resembled the later city so vividly described by Greek writers, although it was probably not of such great dimensions. According to Herodotus, it occupied an exact square on the broad plain, and had a circumference of sixty of our miles. "While such is its size," the historian wrote, "in magnificence there is no other city that approaches to it." Its walls were eighty-seven feet thick and three hundred and fifty feet high, and each side of the square was fifteen miles in length. The whole city was surrounded by a deep, broad canal or moat, and the river Euphrates ran through it. "Here", continued Herodotus, "I may not omit to tell the use to which the mould dug out of the great moat was turned, nor the manner in which the wall was wrought. As fast as they dug the moat the soil which they got from the cutting was made into bricks, and when a sufficient number were completed they baked the bricks in kilns. Then they set to building, and began with bricking the borders of the moat, after which they proceeded to construct the wall itself, using throughout for their cement hot bitumen, and interposing a layer of wattled reeds at every thirtieth course of the bricks. On the top, along the edges of the wall, they constructed buildings of a single chamber facing one another, leaving between them room for a four-horse chariot to turn. In the circuit of the wall are a hundred gates, all of brass, with brazen lintels and side posts."[264] These were the gates referred to by Isaiah when God called Cyrus: I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut: I will go before thee, and make the crooked places straight; I will break in pieces the gates of brass, and cut in sunder the bars of iron.[265] The outer wall was the main defence of the city, but there was also an inner wall less thick but not much inferior in strength. In addition, a fortress stood in each division of the city. The king's palace and the temple of Bel Merodach were surrounded by walls. All the main streets were perfectly straight, and each crossed the city from gate to gate, a distance of fifteen miles, half of them being interrupted by the river, which had to be ferried. As there were twenty-five gates on each side of the outer wall, the great thoroughfares numbered fifty in all, and there were six hundred and seventy-six squares, each over two miles in circumference. From Herodotus we gather that the houses were three or four stories high, suggesting that the tenement system was not unknown, and according to Q. Curtius, nearly half of the area occupied by the city was taken up by gardens within the squares.